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CON 122 Session 2 - Standards and Specifications


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CON 122 Session 2 - Standards and Specifications

  1. 1. CON 122Concrete AdmixturesSession 2Standards and Specifications
  2. 2. Concrete Admixture Definition“A material other thanwater, aggregates, hydraulic cement, and fiberreinforcement used as an ingredient of concreteand mortar added to the batch before or duringits mixing.”
  3. 3. Types of Concrete Admixtures Chemical Admixtures Air-entraining Admixtures Calcium Chloride Admixtures for Flowing Concrete Specific Special Performance Admixtures
  4. 4. Liquid Admixture Standards and Specifications Description Standards / SpecificationsWater-reducing and set-controlling • ASTM C494admixtures • AASHTO M 194 • ASTM C 260Air-entraining admixtures • AASHTO M 154 • ASTM D 98Calcium Chloride • AASHTO M 144Admixtures for Flowing Concrete • ASTM C 1017Specific Performance Admixtures • ASTM C 494
  5. 5. Standard Specification for Chemical Admixtures for Concrete Type A – Water-reducing admixtures Type B – Retarding admixtures Type C – Accelerating admixtures Type D – Water-reducing and retarding admixtures Type E – Water-reducing and accelerating admixtures Type F – Water-reducing, high range admixtures Type G – Water-reducing, high range, retarding ASTM Designation: C 494/C 494M - 99ϵ1
  6. 6. Low water to cement ratio concrete with low chloridepermeability—easily made with high-range water reducers.
  7. 7. Chemical Admixtures Effect Concrete Properties Workability Durability Economics Increase/decrease set time Accelerate strength gain Control Temperature Gain Special Attributes
  8. 8. Chemical Admixtures Dosage Types A, B, and D (2 to 7 oz/100 lbs cementitious material)  Normal dosage: 5-8% water reduction; Type B and D retard set Types C and E  Normal dosage will accelerate set Types F and G (High-range superplastizers)  High dosage at 10-90 oz/100 lbs cementitious material: 12- 25% water reduction  Retards set
  9. 9. ASTM C 494 Physical Testing Requirements ASTM Designation: C 494/C 494M - 99ϵ1
  10. 10. ASTM C 260 Air-Entraining Admixtures 1. Scope*  1.1 This specification covers materials proposed for use as air-entraining admixtures to be added to concrete mixtures in the field. 3.1.1. air-entraining admixture, n – for the purpose of this specification, a material that is used as an ingredient of concrete, added to the batch immediately before or during its mixing, for the purpose of entraining air. ASTM Designation: C 260 - 01
  11. 11. Physical Requirements for Air- Entraining Admixtures ASTM Designation: C 260 - 01
  12. 12. Effects of Using Air-Entraining Admixture Lubrication Effect of air bubbles Reduction of mixing water for equal slump Improved workability Causes sticky finishability
  13. 13. Concrete Producer Adjustments Aggregate Characteristics Proportions of concrete constituents Type and duration of mixing Consistency Temperature Cementitious Materials
  14. 14. Use of Calcium Chloride Accelerate Set Time Induces Corrosion of Metals Aggravate effects of poor quality construction
  15. 15. Use of Calcium Chloride
  16. 16. Consequences of Corrosion in Concrete Cracking Spalling
  17. 17. Corrosion of embedded steelreinforcement is the #1 cause ofpremature deterioration ofconcrete infrastructure in NorthAmerica (and many other regionsworldwide). 17
  18. 18. Calcium Chloride D 98 Requirements
  19. 19. ASTM C 1017 Flowing Concrete Mixtures 1. Scope  1.1 This specification covers two types of chemical admixtures to be added to hydraulic cement concrete mixtures for the purpose of producing flowing concrete. The types are as follows:  1.1.1. Type I – Plasticizing  1.1.2. Type II – Plasticizing and retarding ASTM Designation: C 1017/ C 1017M
  20. 20. ASTM C 1017 Flowing Concrete Admixtures ASTM Designation: C 1017/ C 1017M
  21. 21. New Specific Performance Admixture, Type S Type S, has been added to C 494/ C 494M For admixtures that provide primary specific performance benefits to concrete Other than water reduction, strength, or modification of time of set.
  22. 22. Special Specific Performance Admixtures, Type S